Promotion Effect of Cerium and Cobalt on Cu-ZSM-5 in NO Catalytic Decomposition

In this paper, Ce and Co doped Cu-ZSM-5 catalysts were prepared by liquid phase ion exchange method. Then we characterized its speciality by means of inductively coupled plasma (ICP), X-ray diffractometer(XRD), scanning electron microscope(SEM), H2-temperature programmed reduction(TPR), O2-temperature programmed desorption(TPD) and X-ray photoelectron spectroscopy (XPS), and studied its catalytic decomposition property of NO.The XRD results show that there was no CuO species. H2-TPR characterizations show that the difference of hydrogen consumption between Cu+ and Cu2+ increased after modification of dopig Ce, indicating that Ce improved the Cu species dispersion, prevented Cu(OH)+ aggregation in the solution. At the same time, the competition for exchange site between Ce3+ and Cu2+ leaded to the decrease of Cu2+/Cu(OH)+ and the increase of {Cu2+-O2--Cu2+}2+ active center. The results of O2-TPD indicate that the desorption amounts of amorphous oxygen in the Co-doped sample is larger than that of the undoped sample. Besides, the doping of Co is beneficial to the redox cycle between {Cu2+-O2--Cu2+}2+ and {Cu+-□-Cu+}2+. In general, the synergistic effect of Ce and Co is advantageous to form more active {Cu2+-O2--Cu2+}2+ species and promote its conversion with {Cu+-□-Cu+}2+ during NO decomposition, thus enhancing the decomposition activity of NO. The experimental results proved that the co-doping of Ce and Co into Cu-ZSM-5 catalyst can increase the decomposition rate of NO from 52% to 61% at the space velocity of 1200h-1 and the optimum reaction temperature of 550℃. © 2020 Chin. Soc. for Elec. Eng.